Synthesis and study of organosilicon hydroxymethylated phenols

Article abstract of DOI:10.1134/S1070363212020107

A series of (hydroxymethyl)hydroxyphenyldimethylsiloxanes of linear and branched structures were synthesized by the reaction with formaldehyde in aqueous alkaline medium of organosilicon phenols of general formula R′[Si(CH₃)₂O]_n[Si(CH₃)RO] _mSiMe₂R′, where R′ was 4-hydroxy-3- methoxyphenylpropyl, R was methyl or 4-hydroxy-3-methoxyphenylpropyl. The structure and composition of the siloxanes were confirmed by elemental analysis, NMR and IR spectroscopy. The homocondensation of (hydroxymethyl) hydroxyphenyldimethylsiloxanes at the hydroxymethyl groups was investigated. A possibility of reaction of (hydroxymethyl) hydroxyphenyldimethylsiloxanes with phenol-formaldehyde resin to form copolymers was demonstrated. Pleiades Publishing, Ltd., 2012.

Full text of DOI:10.1134/S1070363212020107

ISSN 1070-3632, Russian Journal of General Chemistry, 2012, Vol. 82, No. 2, pp. 220–225. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © Sh.F. Gizatullin, I.M. Raigorodskii, V.M. Kopylov, 2012, published in Zhurnal Obshchei Khimii, 2012, Vol. 82, No. 2, pp. 224–229.
Synthesis and Study
of Organosilicon Hydroxymethylated Phenols
Sh. F. Gizatullina, I. M. Raigorodskiia, and V. M. Kopylovb
a Penta-91 Co., Volgogradskii pr. 47, Moscow, 119501 Russia
b Research Institute of Chemistry and Technology of Organoelemental Compounds,
sh. Entuziastov 38, Moscow, 111123 Russia
e-mail: shukhart@mail.ru
Received November 11, 2010
Abstract—A series of (hydroxymethyl)hydroxyphenyldimethylsiloxanes of linear and branched structures
were synthesized by the reaction with formaldehyde in aqueous alkaline medium of organosilicon phenols of general
formula R'[Si(CH3)2O]n[Si(CH3)RO]mSiMe2R', where R' was 4-hydroxy-3-methoxyphenylpropyl, R was methyl
or 4-hydroxy-3-methoxyphenylpropyl. The structure and composition of the siloxanes were confirmed by elemental
analysis, NMR and IR spectroscopy. The homocondensation of (hydroxymethyl)hydroxyphenyl-
dimethylsiloxanes at the hydroxymethyl groups was investigated. A possibility of reaction of (hydroxymethyl)
hydroxyphenyldimethylsiloxanes with phenol-formaldehyde resin to form copolymers was demonstrated.
DOI: 10.1134/S1070363212020107
The organosilicon compounds containing reactive
phenol groups at the silicon atom are of interest as the
starting monomers and oligomers for obtaining various
silicon-containing polymers [1]. It is reasonable to use
the organosilicon phenols as modifiers of organic
resins and compositions for adding properties of heat
and frost resistance, water repellency, etc. to organo-
elemental and organic materials [2–4]. A method for
production of organosiloxane phenolic resins based on
the products of high-temperature condensation of
alkoxysilanes and siloxanes with organic bisphenols
has been claimed [5]. A synthesis of copolymers by
polycondensation of organosilicon phenols with
organic hydroxymethylphenols was reported [6]. The
(hydroxymethyl)hydroxyphenyldimethylsiloxanes con-
taining both phenol and hydroxymethyl functional
groups have been described [7].
In this paper we discuss the features of the method
of synthesis and properties of carbofunctional (hyd-
roxymethyl)hydroxyphenyldimethylsiloxanes of linear
and branched structure. The presence in their structure
of hydroxymethyl and phenol reactive groups enhances
their performance as a source reagents for the synthesis
of copolymers and modifiers of organic polymers.
Synthesis of (hydroxymethyl)hydroxyphenyl-di-
methylsiloxanes was performed by hydroxymethyla-
tion of the organosilicon phenols [4] of general
formula R'[Si(CH3)2O]n[Si(CH3)RO]mSiMe2R', where
R' is 4-hydroxy-3-methoxyphenylpropyl group, R is
methyl or 4-hydroxy-3-methoxyphenylpropyl group,
with formaldehyde in aqueous alkaline medium.
NaOH + HO
H3CO
(CH2)3 Si
NaO
(CH2)3 Si
+ H2O
H3CO
HOH2C
CH2O + NaO
H3CO
(CH2)3 Si
NaO
H3CO
(CH2)3 Si
220

SYNTHESIS AND STUDY OF ORGANOSILICON HYDROXYMETHYLATED PHENOLS
221
HOH2C
NaO
H3CO
HOH2C
HO
+ HCl
+ NaCl
(CH2)3 Si
(CH2)3 Si
H3CO
The para- and ortho-positions relative to the OH
group in the phenyl radical of the source phenol are
occupied by propylsilyl and methoxyl substituents,
respectively. Therefore, the hydroxymetylation is possible
only at the unoccupied ortho-position in the phenol
fragment. The optimum conditions of the synthesis are
pH 10–11 and temperature from +35 to +45°C. At pH <
10 the reaction proceeds slowly. At pH > 12 and at higher
temperatures the process is complicated by the poly-
condensation reaction. As a result a series of mono-
mers and oligomers differing by the lengths of siloxane
chain and the location of 3-[4-hydroxy-3-(hydroxy-
methyl)-5-(methoxyphenyl)]propyl substituent was
obtained:
HOCH2
HO
CH3
(CH2)3 Si
CH3
O
H3CO
2
I
(CH3)3Si
O
Si(CH3)
(CH2)3
O
Si(CH3)2
O
Si(CH3)3
8
32
HOCH2
OCH3
OH
II
HOCH2
HO
CH2OH
OH
(CH2)3 Si(CH3)2
O
Si(CH3)2
(CH2)3
29
H3CO
OCH3
III
(CH3)3Si
O
Si(CH3)
(CH2)3
O
Si(CH3)3
HOCH2
OCH3
OH
IV
The products of hydroxymethylation are dark yellow
liquids of different viscosity, well soluble in chlo-
rinated hydrocarbons, toluene, and ethanol.
The structure of compounds I–IV was confirmed
by NMR and IR spectroscopy and elemental analysis.
The NMR spectra indicate the presence of proton
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222
GIZATULLIN et al.
(a)
(b)
δ, ppm
1H NMR spectrum of (a) compound IV and (b) initial phenol.
Table 1. Chemical shifts in the 1H NMR spectra of (hydroxy-
methyl)hydroxyphenylorganosiloxanes
signals with chemical shifts characteristic of hydroxy-
methyl group (see Table 1 and the figure). The IR
spectroscopy data show that while the absorption band
of the phenol OH group in the spectrum of the initial
organosilicon phenol falls into the region of 3513 cm–1,
in the spectra of (hydroxymethyl)hydroxyphenyl-
dimethylsiloxanes the presence of hydroxymethyl
groups leads to the shift of the OH absorption band to
the region of 3375 cm–1. The properties of the syn-
thesized compounds are listed in Table 2.
Group
δ, ppm
Si–CH3
Si–CH21–CH22–CH23
0.00–0.16
0.45–0.65 (CH21), 1.54–1.75 (СН22),
2.45–2.66 (СН23)
3.70–3.85 (СН21), 5.45–5.55 (СН22),
5.45–5.55 (СН23), 4.60–4.74 (СН24),
6.75–6.79 (СН25)
H13CO
H2O
H5
Table 2 shows that the values of dynamic viscosity
of compounds I and III are 1925 and 177 cP,
respectively, while those of the original phenols are
respectively 910 and 60 cP. Higher viscosity of the
(hydroxymethyl)hydroxyphenyldimethylsiloxanes com-
pared to the initial phenols may be related to the
formation of additional hydrogen bonds due to the
presence of the CH2OH groups.
H3O_H42C
H1
H5
H
7.00–7.10 (СН1)
HO
HOH2C
H
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SYNTHESIS AND STUDY OF ORGANOSILICON HYDROXYMETHYLATED PHENOLS
223
Table 2. Some characteristics of organosilicon hydroxymethylphenols
Comp.
Name
d, g cm–3
М, g mol–1
nD20
μ, cP
no.
1,3-Bis-[3-(4-hydroxy-3-hydroxymethyl-5-methoxyphenyl)propyl]-
tetramethyldisiloxane
1.09
523
1.5200
1925
I
α,ω-Hexamethyl-octa-[3-(4-hydroxy-3-hydroxymethyl-5-methoxy-
1.070
1.01
4562
2594
1.4630
1.4270
3605
177
II
phenyl)propyl]oligodimethylsiloxane 8/32
α,ω-Bis-[3-(4-hydroxy-3-hydroxymethyl-5-methoxyphenyl)propyl]-
III
oligodimethylsiloxane-30
1,1,1,2,3,3,3-Heptamethyl-2-[3-(4-hydroxy-3-hydroxymethyl-5-
methoxyphenyl)propyl]trisiloxane
1.029
416
1.4875
230
IV
By an example of compound IV we investigated
heating to 150°C occurs the formation of ether bonds –
CH2–O–CH2– (s, δ 4.75 ppm), and then at the tem-
perature above 200°C, methylene bridges (s, δ 4.71 ppm)
similarly to [8].
the condensation of the hydroxymethylated com-
pounds at the CH2OH groups proceeding at heating. It
1
is confirmed by the H NMR spectroscopy that at
H3CO
HO
H2C
(CH2)3 Si
HOH2C
150oC
_H2O
O
2 HO
H3CO
(CH2)3 Si
H2C
HO
(CH2)3 Si
H3CO
H3CO
HO
H3CO
(CH2)3 Si
HO
H2C
HO
H3CO
(CH2)3 Si
H2C
H2C
200oC
_CH2O
O
(CH2)3 Si
HO
H3CO
(CH2)3 Si
Compound IV with one hydroxymethyl group in
the molecule can form only a dimer, while compounds
I and III, containing two CH2OH group, at heating to
150–200°C form soluble linear condensation products.
Investigation of the product of polycondensation of
compound by size-exclusion chromatography
showed that it is an oligomeric compound comprising
molecules differing by the degree of polycondensation,
I
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224
GIZATULLIN et al.
Table 3. Thermogravimetric analysis of resites based on phenol-formaldehyde resin and compound II
Temperature of the sample weight loss, °C
Material
Residue at 800° C, wt %
5%
20%
50%
Rezite
366
525
631
31.2
41.7
46.6
Rezite + 5% of modifier
Rezite + 10% of modifier
388
390
556
563
648
652
with molecular masses in the range 1078–6046 g mol–1.
The molecular-mass characteristics of the product of
polycondensation of compound I also confirm that it
has a broad polydispersity:
leads to an increase in the glass transition temperature
of the samples from 146 to 160°C.
EXPERIMENTAL
Mn
Mw
Mz
Mw/Mn Content, %
8.62 98.5
The IR spectra were recorded on a Vector-22
Bruker FTIR spectrometer in the range ν 400–
4000 cm–1. The gel-permeation cromatography was
performed on an instrument from Knauer company,
with a refractometric detector, Stirogel column, and
THF as eluent. The NMR data were obtained on a
Bruker AT 360 MHz NMR spectrometer.
870
7500
45500
The multifunctional compound II on heating at
150°C for 20 min affords a polycondensation product,
which is soluble in toluene, chloroform, and isopropyl
alcohol. Raising the temperature to 200°C and keeping
the sample for 20 min produces a substance insoluble
in these solvents. This can be explained by deeper
condensation and, consequently, cross-linking of the
oligomer with the formation of methylene bridges.
The thermogravimetric analysis was performed on
a Perkin Elmer TGS-2 termoanalyzer, heating rate
10°C min–1, temperature range 40–800°C. The
measuring of the glass transition temperature (dilato-
metric analysis) was performed on the same Perkin
Elmer TGS-2 termoanalyzer, heating rate 5°C min–1,
temperature range 50–250°C. Sample dimensions:
height 1–1.5 mm, width 2–3mm. The diameter of the
flat end of a quartz rod of the measuring device 3.5 mm.
The preliminary calibrated chrome-aluminum thermo-
couple is located at the 1–1.5 mm distance from the
sample. The load required for the desired contact of the
rod with the sample 1 g. The transition from the glassy
to the viscoelastic state is displayed on the plot of the
size (height) of the sample on temperature as a jump in
the narrow temperature range. As the Tg is adopted the
point of intersection of the tangents to the curve
branches.
The synthesized compounds were used also as
modifiers of organic polymer by an example of
phenol-formaldehyde resins of resol type, obtained by
the procedure [9]. We selected as the modifier
compound II. Modification of phenol-formaldehyde
resin with the (hydroxymethyl)hydroxyphenyldi-
methylsiloxane should proceed through the co-con-
densation of hydroxymethyl groups of organic and
organosilicon oligomers to form a block copolymer.
We prepared three compositions: individual resol, and
the resols containing 5% and 10% by weight of
hydroxymethylated oligosiloxane. These compositions
were heated at 200°C for 1 h. Analysis of the modified
products showed content of the sol-fraction in them of
1% by weight. This confirms the high level of forma-
tion of the copolymer with three-dimensional structure.
Dynamic viscosity was measured on a Brookfield
DV-E viscometer, no. 28 spindle, rotation speed
100 rpm. The tested oligomer is poured into a steel cup
to the mark, the cup is fixed in thermally controlled
jacket. The rotation speed is set after the temperature
stabilization.
To assess the thermal stability of the obtained com-
positions we carried out the thermogravimetric
analysis of the obtained resites in air (Table 3).
As can be seen, the modified samples are by 20–
30°C more stable thermally compared with the un-
modified ones.
1,3-Bis-[3-(4-hydroxy-3-hydroxymethyl-5-methoxy-
phenyl)propyl]tetramethyldisiloxane (I). The reac-
tion flask equipped with a thermometer, a reflux
condenser and a stirrer, was charged with 4.86 of
Modification of phenol-formaldehyde resin with
(hydroxymethyl)hydroxyphenyldimethylsiloxanes also
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SYNTHESIS AND STUDY OF ORGANOSILICON HYDROXYMETHYLATED PHENOLS
225
NaOH and 3.781 ml of water, and 50.1711 g of α,ω-
bis-[3-(4-hydroxy-3-methoxyphenyl)propyl]tetramethyl-
disiloxane was added dropwise with stirring. After the
viscous mass formation, 133 ml of 37% aqueous solu-
tion of formaldehyde was added. The reaction mixture
was stirred at 40°C for 4 h, then 10.98 ml of 35%
aqueous HCl was added. After separation of layers, the
reaction mixture was diluted with 100 ml of CHCl3.
The lower layer, the solution of the reaction product in
CHCl3, was seprated in a separating funnel from the
upper water layer, and washed with water to pH 7. The
solvent, water, and the remaining CH2O were distilled
off at 60°C (133 Pa) on a rotary evaporator. 53.6 g
(95% yield) of 1,3-bis-[3-(4-hydroxy-3-hydroxy-
methyl-5-methoxyphenyl)propyl]tetramethyldisiloxane
was obtained. Found, %: C 61.52, H 8.82, Si 11.17.
C32H42O7Si2. Calculated, % C 59.73, H 8.1, Si 10.74.
geneous transparent mass of dark amber color, soluble
in toluene, chloroform, and aliphatic alcohols.
Preparation of compositions based on the
phenol-formaldehyde resins. A phenol-formaldehyde
resin of resol type was divided into three portions,
which were placed in glass cups. To two samples was
added 0.8 g (5 wt %) and 1.6 g (10 wt %), respectively,
of compound II at continuous stirring.
For the preparation of 5% modified rezite, the
fluoroplastic mold was filled with 3 g of 5% of the
modified resol, the mold was placed in a vacuum oven
and heated at 120°C for 60 min. Then temperature was
raised to 200°C and heating was continued for 60 min.
After cooling to room temperature, a product as an
opaque solid glassy mass insoluble in ethanol was
obtained. Analysis for the gel fraction showed the
presence in the condensation product of 1% of ethanol-
soluble substances.
α,ω-Hexamethylocta-[3-(4-hydroxy-3-hydroxy-
methyl-5-methoxyphenyl)propyl]oligodimethyl-
siloxane 8/32 (II) was prepared analogously to
compound I. Yield 94% (38.78 g). Found, %: C 3.82,
H 8.15, Si 26.81. C166H354O65Si42. Calculated, % C
3.64, H 7.56, Si 25.78.
The 10% modified rezite was prepared similarly.
Analysis showed the presence in the condensation
product of 1% of sol fractions.
REFERENCES
α,ω-Bis-[3-(4-hydroxy-3-hydroxymethyl-5-
methoxyphenyl)propyl]oligodimethylsiloxane-30
(III) was prepared analogously to compound I. The
yield of product III 96% (26.98 g). Found, %: C 2.53,
H 7.31, Si 33.98. C82H210O35Si30. Calculated, % C
2.39, H 7.17, Si 32.38.
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mov, M.R., and Zhdanov, A.A., Vysokomol. Soedin., A,
1987, vol. 29, p. 2441.
2. US Patent no. 4923912, 1990.
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4. RF Patent no. 2211845, 2001.
5. Germany Patent no. 937555, 1956.
6. Greber, G., Angew. Makromol. Chemie, 1968, vol. 4,
no. 41, p. 212.
7. RF Patent no. 2397994, 2010.
8. Slonim, I.Ya. and Urman, Ya.G., YaMR-spektroskopiya
geterotsepnykh polimerov (NMR Spectroscopy of
Hetero-Chain Polymers), Moscow: Khimiya, 1982,
p. 173.
9. Nikolaev, A.F., Tekhnologiya plasticheskikh mass
(Technology of Plastics), Leningrad: Khimiya, 1977,
p. 174.
1,3-Hexamethyl-2-methyl-2-[3-(4-hydroxy-3-hyd-
roxymethyl-5-methoxyphenyl)propyl]trisiloxane
(IV) was prepared analogously to compound I. Yield
94% (48.0 g). Found, %: C 54.47, H 8.54, Si 21.03.
C18H36O5Si3. Calculated, % C 51.88, H 8.71, Si 20.22.
Condensation of compound I. A fluoroplastic
mold charged with 3.3 g of 1,3-bis-[3-(4-hydroxy-3-hyd-
roxymethyl-5-methoxyphenyl)propyl]tetramethyldi-
siloxane was placed in a vacuum oven and heated at
200°C for 60 min, then cooled to room temperature.
The resulting product was a resinous plastic homo-
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 82 No. 2 2012